Question

What is the rounding or compatible number of 256+321

Answer 1

256 would round to 300 and 321 would round to 300. 300+300 = 600
Hope thats what you were looking for!

Answer 2

Compatible numbers for 256...
1. Rounded to the nearest hundred = 200
2. Rounded to the nearest tens place = 260

Compatible numbers for 321...
1. Rounded to the nearest hundred = 300
2. Rounded to the nearest tens place = 320

I hope this helps! :)